There are certain instances where it is absolutely crucial that a correct and accurate proportion between two or more liquids is maintained, which is not easily accomplished particularly when the liquids are immiscible in one another. As an example of a use to which such a device can be made is in the determination of the amount of water in crude oil, particularly as it is transported and stored in present day super-tankers.
As oil prices have escalated in recent years, oil companies have sought more effective methods of determining the true "bottom sediment and water" content, commonly called BS&W, in the oil they purchase. BS&W comes from a variety of sources in the oil ranging from water and sediment pumped up from the bottom of an oil well to sea water taken on board a ship during the sea voyage which is used as ballast. Since the purchaser pays for the oil based on total volume received, it becomes important to know what percentage of the shipment is BS&W.
In calculating the BS&W, the purchaser follows a well accepted procedure of withdrawing a small sample of the oil unloaded from the super-tanker every few seconds. This sample is put into a small tank and, every few days, or as the tank becomes full, the contents of the tank are mixed and a small sample taken from it for analysis for BS&W content. Often, even though the sampling process is accurate, the method of mixing the tank full of oil and water is ineffective, leading to inaccurate analyses. Since an entire ship load averaging some 450,000 barrels will be analyzed on the basis of 121/2 to 25 mls. of sample oil, a small error of, for example, 0.1% can lead to a sizeable difference in the value of the cargo ($11,700 based on a 0.1% error at oil selling for $26.00 per barrel). Unfortunately, prior to the present invention, there has appeared to be no accurate means of maintaining uniform proportion between two or more liquids, such as crude oil and water, to insure the accuracy of the sampling analysis as described above.
It is thus an object of the present invention to provide such a device capable of maintaining a substantially uniform proportion between two or more liquids at a speed and accuracy unavailable by prior devices.